[A comparative study of clinical score and lung function tests in the classification of asthma by severity of disease].

Fifty nine asthmatic children and adolescents, clinically stable, aged 6 to 15 years, 37 boys and 22 girls, from Instituto da Criança do Hospital das Clínicas da FMUSP, were studied from September to November, 1994. The patients were classified by the clinical score of the International Consensus for Asthma Diagnosis and Management. They performed baseline spirometry and peak expiratory flow rates (PEFR), before and after bronchodilator, and measured PEFR three times a day (6 pm, at bedtime and on waking), for one day, at home. Five PEF measurements were made serially and the best readings were considered. Variability of PFE was calculated for 24 hours, as assessed by maximal amplitude. The results were summited to statistical analysis of the Laboratorio de Informática Médica da Faculdade de Medicina da USP. The results of PEFR and it's variability were compared to spirometry, (functional score, FEV1-forced expiratory volume in the first second) and to the clinical score of the International Consensus for Asthma Diagnosis and Management. In case of disagreement between the clinical parameters, the more severe one was chosen. The clinical score classified 20.3% of our patients as mild obstruction, 49.2% as moderate and 30.5% as severely compromised. According to FEV1, 58% of patients were classified as normal while the PEFR and its variability classified as normal 76% and 71%. The PEFR and it's variability in 24 hours, correlated with the VEF1, as gold standard, showed good specificity, 91% and 76% respectively and low sensibility, 44% and 32%. It was detected a low level of agreement between FEV1, PEFR and it's variability in 24 hours, in the clinical severity classification of asthma. The results of this study showed that FEV1 and PEFR had a low level of agreement in the clinical severity classification of asthma and when they were correlated to the clinical score of the International Consensus, they both presented low sensitivity.